FXUS61 KBTV 180509
Area Forecast Discussion
National Weather Service Burlington VT
109 AM EDT Sun Aug 18 2019
Scattered showers and strong thunderstorms will push east of
Vermont late this evening as an upper level disturbance departs
across northern Maine tonight. Humid air will linger in place
across the North Country with patchy fog overnight, especially
in locations that received rainfall. A few additional showers
and isolated thunderstorms will redevelop on Sunday. Valley high
temperatures will again reach the mid 80s in most locations.
Additional showers and thunderstorms are possible during the
first half of the work week before a cooler air mass settles in
across New York and northern New England toward the end of the
.NEAR TERM /UNTIL 2 PM THIS AFTERNOON/...
As of 102 AM EDT Sunday...Water vapor shows large scale
subsidence behind departing s/w energy with some leftover mid
level clouds per ir trends. However, any location that has
received rainfall and a period of clearing has already developed
fog. So have expanded the fog/br in grids, which includes
portions of the slv and cpv, as well as climo favored areas.
Otherwise, temps/dwpts and rest of fcst on track.
Excerpts from prior discussion...
On Sunday, brief shortwave ridging occurs with quiet weather
during the morning hours. A modest mid-level vort arriving in
wswly flow may yield a few additional showers and thunderstorms
during the peak heating hours, and included 20-30 PoPs to cover
this potential during the afternoon. Very warm and humid
conditions otherwise, with highs again 82-86F in most valley
.SHORT TERM /2 PM THIS AFTERNOON THROUGH MONDAY NIGHT/...
As of 301 PM EDT Saturday...Monday will be the warmest day of
the week as continued warm air advection allows 925mb temps to
climb to 22+ deg C, supporting surface temperatures in the mid
80s to near 90. Humidity will also be on the rise with dewpoints
rising into the upper 60s to near 70 as a warm front moves
through. Forecast soundings suggest afternoon mixing will reduce
dewpoints during peak heating hours, which will keep heat
indices somewhat in check...with heat indices in the upper 80s
to low 90s expected. Will have to watch the trends in cloud
cover with the warm front pushing through -if cloud cover is
more than expected we`d underachieve on afternoon highs. There
will be some showers and thunderstorms that pop up during the
afternoon hours amid the unstable air mass, mainly terrain
driven due to the lack of focused forcing. A cold front will
move through from the northwest to southwest early Monday
night, putting an end to any remaining showers as drier air is
ushered in from the northwest. The remainder of the night will
be dry with lows in the low to mid 60s.
.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 301 PM EDT Saturday...Forecast trending a little less
unsettled for the long term time range as the better instability
and moisture next week looks now to mainly stay to our south.
Most noticeable change to the forecast is to trend Tuesday drier
with rising confidence in high pressure building in at the
surface and subtle 500 mb height rises over the area. Although
925 mb temps won`t be quite as warm as Monday`s, solar heating
will offset the slightly cooler air and temperatures will again
rise into the mid 80s. Tuesday will, however, be noticeably
less humid than Monday given the drier air moving in from the
northwest. Wednesday and Wednesday night are still on track to
be rather wet as a cold front sweeps through, resulting in
showery conditions mid week. Once the front clears the area,
expect cooler and drier temperatures to return for the end of
the week with highs in the 70s and lows in the 50s.
.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
Through 06Z Monday...Challenging early morning aviation forecast
with regards to low clouds and fog/br development. Crnt
conditions vary from lifr at slk/pbg to ifr for cigs at mpv to
vfr at btv/mss/rut. Thinking fog is most likely to prevail at
slk/mpv from 06z thru 12z or so, given saturated bl conditions
and crnt obs. Meanwhile, thinking intervals of ifr/lifr is
likely at pbg/mss and rut, given the recent rainfall and very
small temp/dwpt spread. At btv a period of mvfr with fog deck
nearby is possible around sunrise, but will continue to monitor
for potential clouds and associated impacts at all sites.
Otherwise, any ifr should lift by 12z with mainly vfr conditions
from 12z through 00z Monday, with some threat for showers/storms
Monday: VFR. Chance SHRA, Chance TSRA.
Monday Night: VFR. Slight chance SHRA.
Tuesday: VFR. NO SIG WX.
Tuesday Night: VFR. Chance SHRA.
Wednesday: VFR. Chance SHRA, Chance TSRA.
Wednesday Night: VFR. Chance SHRA, Slight chance TSRA.
Thursday: Mainly VFR, with local IFR possible. Chance SHRA.